First off, I want to apologize for the low quality pictures. My only digital camera is the one in my phone and its obviously not great.
I would estimate that the finish is most likely original. I conclude this by looking at the etchings of the flaps, horizontal stabilizers, gear doors, etc. under a magnifying glass. They were definitely etched after the model was painted/finished. The finish is of good thickness as evidenced at one of the small chips on the tail.
I have no idea whether or not the decals are original. They appear aged as if they were. The blacked out front windshield is of particular detail and most likely would have had to been done at production. The engine intakes and exhausts are not recessed and are both painted black and show wear. The port entry hatch is also black paint. Or were these black out areas all decals themselves?
I am not sure if the stand is original but believe there is a good chance it is as evidenced by the wear on the bottom of the fuselage where it holds the model. None of the wear on this area extends beyond where this mounting touches the model. This is true no matter which way the aircraft is set upon the stand. According to the wear, it appears that this is the only stand that has ever held this model. The base of the stand is made of two identical pieces of wood except the one on top is smaller than the base. The arm is a tarnished, bronze colored metal.
Finally, I came across a picture of a very similar model at this link:
http://www.art-aviation.com/galerie10-Milit.htm (scroll down to the bottom of the page an you will see the Valiant.) The decal on the tail of this model is different and the windshield paint is different as well. Mine has two panes that have diagonal lines through them. Otherwise, it looks to be the same model.
I really appreciate your response. Solving this mystery has been a great experience and I will follow your advice and ask Bryan if he can further narrow it down for me.